i'm sorry but Churchill warned EVERYBODY about Stalin but they didn't listen, don't lay this one on Churchill because he could already foresee what would happen with Stalin :)
Actually Churchill was a very interesting and tragic figure of WWII. He criticized Chamberlain for his appeasement politics towards Hitler just to do the same later on with Stalin. It's worth writing that in contrary to English post WWI government he was very pro Polish and very pro any other new established countries in the between the wars period. For example during the Polish Bolshevik war he convinced British government to send some aid for the polish army. Unfortunately, this aid never reached its destination as the English Dockers sabotage it, but that's just a whole different story.
Still despite his positive attitude towards Poles and Poland he did lead a very double faced politics towards them. He perfectly knew about Stalin’s plans regarding Poland, which BTW Stalin was always open about. He cold have stopped cooperation between our two nations when The Soviets joined the Allies, but he didn't want to gave up on Polish intelligence, polish soldiers both abroad and in the home army, etc so he continued to deceive Polish government and avoid answering the question what will happen with Poland after the end of WWII. We can't blame him of bad will towards us. As most English men, he was a pragmatic. His responsibility was to protect his fellow country men and not some people of central (or as it seem these days, eastern) Europe and it was obvious that any form of attack on Russia at that time would be suicidal. We can't blame him for protecting his people, however I don't think it is too much to ask to understand, that after so many promises being made by him during the BOB and after sacrificing so much, my grandfather and other polish soldiers of that time felt bitter, abandoned and betrayed.
As for Americans selling us out, we never had any treat signed between our governments nor did Roosevelt ever promised us anything, so I don't think that we can talk here about "selling us out". (I'm also against saying that the UK sold us out BTW)
if that kind of war would happen we are naturaly on side of UK or US ... I know our history and relationship are complicated (we have to change a lot in this case) but all in all we share the same values.
Taking under consideration today’s Poland, I'm sure you are right. I was just expressing my point of view and what I think would be the best for Poland, and declaring war against Russia would definitely be a very foolish thing to do.
The whole idea about a USA vs China/Russia/Iran armed conflict seems pretty much surreal, especially the UK joining in part (such recklessness is not their style), but if it would be the case, than to declare war against Russia would mean that on the territory of Poland there would be one of possible fronts. At this point emerges a question, do you think that the UK and USA would send their troops to defend, strategic-wise, not a very important point like Poland? I think that history gives us a hint how the whole situation could have turned out. :)
Basically, I would do what Americans did during WWII: sit back and watch how the major players bleed themselves out... Risking the lives of millions of innocent civilians and the state of economy for dubious honor of standing in the front line isn't a good business at all. The only thing that we would gain by doing so would be earlier mentioned honor and fame, which as history shows us, doesn’t last long. After 60 years or so, our grand children mentioning our heroic deeds would be probably called backward and accused of living in the past any way. LOL :)) So what's the point?